Few studies have researched the effects of off-road vehicles (ORVs) on trail surfaces in humid regions, particularly the ability of soil models to estimate erosion, the geomorphic change in the trail surface, or the effectiveness of grade reversals in reducing erosion. This research examines cross-trail profile measurements of 11 ORV trail segments in southeastern Ohio over a six month period in order to calculate the erosion occurring in both the ORV riding season and the off season. Field measurements are compared to the output of two soil erosion models, WEPP and WEPP:Road. Spatial patterns of erosion, compaction, and soil texture, and the geomorphic change in the trail surface are also analyzed.
Results show that both WEPP and WEPP:Road models grossly underestimate the amount of soil erosion measured on the studied trail segments. The highest measured erosion rate totaled 116 kg/m2/yr. Significant geomorphic changes in cross-trail profiles were not detected during the six month study. Spatial patterns reveal the dominance of erosion over the study period for upslope and mid-slope locations, and a tendency for deposition at segment-bottom locations just upslope from grade reversals, proving the effectiveness of some of the grade reversals. Statistically significant higher compaction values were found in the tire ruts and along the inside strip of the trail, compared to the outside edges. Surface materials at the slope bottoms were significantly sandier and contained clay than surface materials at the midslopes or the top of the slopes. Results of this study demonstrate spatial patterns of soil erosion and compaction on the ORV trail surfaces and the need for improved models for predicting soil erosion from ORV trails.